Did he have synesthesia?
Was he a writer?
Was he ambidextrous?
Did they want to examine his brain?
Was he noted as a genius?
Was he a composer?

A surprising No to all of those. I offer the following clues:

1. You've established that he was French and known for his work in the arts - it was the performing arts for which he was famous.
2. I doubt anyone would know his real name, a few would know his stage name but almost everyone on this site would have heard of his performances, even if it was quite vague.

Yes - Rob_Bob's got it. The Sorbonne offered 25,000 francs to examine the body of Le Pétomane the famous French flatulist who was a national celebrity at the turn of the 19th/20th centuries, Apparently he did not fart in the true sense of the word but was able to inhale air into his arse due to some anatomical abnormality. I was going to offer as a clue that his real surname as pronounced in France was actually the same as the body part that the scientists wanted to examine but that would have been too tacky...

I was writing a quiz round for a friend and one of the answers struck me as being a good candidate of rone of these and we haven't had one for ages. It's a little easier than some of them so shouldn't be any trouble to quizzes of your calibre.

A TV pub's original landlord had a fictional birthplace which was 5 miles from the birthplace of a real life person with exactly the same christian and surname. They were exactly the same age when they died and the name of the TV pub could be said to have been the real life person's most famous achievement. What was their shared name?